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UNITED STATES DEPARTMENT OF AGRICULTURE 




s^^'^^^j-u 



BULLETIN No. 503 i 



Contribution from the States Relations Service 
A. C. TRUE, Director 




Washington, D. C. 



PROFESSIONAL PAPER 



March 6, 1917 



TURNIPS, BEETS, AND OTHER SUCCULENT 
ROOTS, AND THEIR USE AS FOOD. 

By C. F. Langwoethy, Chief, Office of Home Economics, States Relations 

Service. 



CONTENTS. 

Page, j 

Introduction , 1 j Roots used as condiments. 

Food value of succulent roots 3 Summary .^ 

Root vegetables less commonly known. 14 ! 



Page, 
15 
17 



INTRODUCTION. 

The succulent roots, so called because water (juice) makes up so 
large a part of their edible substance, include such common and 
long-known vegetables as turnips, parsnips, radishes, carrots, salsify, 
beets, celeriac, onions, and garlic. In the same general group belong 
also a few roots which are used as condiments or spices rather than 
for their food value, the most common being ginger and horse-radish. 

The succulent roots which are grown as garden vegetables have 
undoubtedly all been developed from wild forms, though, as is the 
case with many other plants which have been under cultivation for 
centuries, the wild forms of most of them are not definitely known. 
It can be said with certainty, however, that as the}^ have come under 
cultivation the roots have increased in size, the texture has become less 
tough, and the flavors have been modified. Those here grouped to- 
gether include such diverse forms as bulbs, roots, stalks, root-stocks, 
and tubers. It is evident, therefore, that from the botanist's stand- 
point this use of the term " roots " is not accurate ; it has come into 
use in discussing the matter from a household standpoint doubtless 

Note. — This bulletin is of special interest to housekeepers and to home economics 
extension workers, teachers, and students. It summarizes data regarding the nature, 
uses, and food value of succulent roots. 

70537°— Bull. 503—17 1 



2 BULLETIN 503^ U. S. DEPAETMENT OF AGEICULTUEE. 

for the lack of a more exact yet simple word, and is here used be- 
cause of its convenience as a general descriptive term. 

As a whole, " succulent roots " and " starchy roots," ^ the two 
great groups into which edible roots are commonly divided, together 
constitute one of the most important sources of food. 

The succulent vegetables owe their popularity in considerable 
measure to their good keeping qualities. After harvesting in the 
late autumn, they will keep in a cellar, or other cool storage place, 
for a long time in reasonabl}^ good condition, though as the season 
advances they may become somewhat tough and strong in flavor. It 
is a common custom in the Horthern States to store such vegetables 
in sand rather than in bins or boxes, and some sorts, such as parsnips 
and oyster plant, are frequently left in the ground and dug in early 
spring. In the parts of the United States where the weather is mild 
and yet too cool to permit growth, this is an especially common 
method of keeping winter vegetables, for it is possible to dig them 
at almost any time during the winter. 

Now that cold storage and improved methods of transportation 
have made it easily possible to secure a greater variet}^ of vegetables 
at all times of the year than was formerly the case, the stored root 
vegetables are relatively less important. This does not mean that 
their use is likely to disappear, but rather that the northern markets 
are being supplied also with more delicate varieties; for instance, 
small tender beets, which many would prefer to the larger and 
tougher ones commonly stored for winter use. In southern markets 
one can obtain such vegetables fresh a good part of the year. 

The usefulness of root vegetables is not limited to their under- 
ground portions, since in many cases the leaves and stems, when 
young and tender, are good as potherbs. Most commonly used are 
beet tops and turnip tops, but radish and horse-radish leaves also 
make good " greens," especially for mixing with greens of milder 
flavor, and occasionally carrot tops are also used for this purpose. 
The careful housekeeper who buys beets and turnips by the bunch 
will save and use the tops for greens. If she has a garden she will 
use the young plants when they are thinned out, and may also often 
get a dish of greens by picking tender leaves here and there from her 
garden bed of beets or turnips. The young green tops of onions are 
much used for seasoning and are also tender and palatable when 
cooked as a vegetable. Celeriac tops, too, are useful as a seasoning. 

Most of the common succulent vegetables — ^turnips, beets, parsnips, 
carrots, etc. — are biennial plants, and if by any chance the roots re- 

^The nutritive value and uses of starchy roots have been discussed in U. S. Dept. 
Agr. Bui. 468 (I916,i. Recipes for proparinj? such vegetables for the table will be found 
in U. S. Dept. Agr. Farmers' Bui. 256 (1906). 



SUCCULENT ROOTS AND THEIR USE AS FOOD. 3 

main in the ground and are not killed, they will start to grow and 
send up their flower stalks and bear seed. This is, of course, the 
purpose for which nature designed the reserve material stored up 
in the roots which we use as food. This second-year growth may be 
turned to advantage for the table ; a surplus of turnips, too wilted for 
table use, may be planted out in spring and, while the leaves are still 
tender, will furnish a crop of good greens, or may be added to salads 
if one prefers. 

FOOD VALUE OF SUCCULENT ROOTS. 

Many factors may be considered in deciding on the food value of 
any material, but one which must be taken into account is its 
chemical composition. When that has been learned, there is a 
definite basis for discussing its value in supplying the protein essen- 
tial as a source of "nitrogen for use in tissue building and which also 
supplies energy, the energy-yielding starches, sugars, and fats, the 
tissue-building and bodj^-regulating mineral matters, and so on. 
The following table presents these facts regarding the more impor- 
tant succulent roots : 

Average composition of succulent roots, tuhers, and hulbs. 



Kind of vegetable. 



Beets, fresh 

Beets, cooked 

Celeriac 

Carrots, fresh 

Carrots, desiccated 

Parsnips 

Salsifj^, "oyster plant'' 

Black salsify 

Radishes 

Turnips, white 

Turnips, yellow (rutabagas). 

Kohl-rabi 

Onions 

Garlic 

Potatoes 

Horse radish 



Refuse, 



Per 
cent. 
7.0 



Edible portion. 



Water. 



20.0 
20.0 



20.0 
25.0 
20.0 



10.0 
10.0 
20.0 
30.0 



20.0 



Per 

cent. 
87.5 
88.6 
84.1 
88.2 
3.5 
83.0 
85.4 
80.4 
91.8 



91.1 

87.6 
64.6 
78.3 
76.7 



Pro- 
tein. 



Per 
cent. 
1.6 
2.3 
1.5 
1.1 
7.7 
1.6 
4.3 
1.0 
1.3 
1.3 
1.3 
2.0 
1.6 
6.8 
2.2 
2.7 



Fat. 



Per 
cent. 

0.1 
.1 
.4 
.4 

3.6 
.5 
.3 
.5 
.1 
.2 
.2 
.1 
.3 
.1 
.1 
.4 



Carboh 


y^drates. 


Ash. 


Sugar, 

starch, 

etc. 


Crude 
fiber. 


Per 


Per 


Per 


cent. 


cent. 


cent. 


8.8 


0.9 


1.1 


7 


4 


1.6 


11.8 


1.4 


.8 


8.2 


1.1 


1.0 


8( 


.3 


4.9 


11.0 


2.5 


1.4 


6.8 


2.0 


1.2 


14.8 


2.3 


1.0 


5.1 


.7 


1.0 


6.8 


1.3 


.8 


7.3 


1.2 


1.1 


4.2 


1.3 


1.3 


9.1 


.8 


.6 


26.3 


.8 


1.4 


18.0 


.4 


1.0 


15.9 


2.7 


1.6 



Fuel 
value 

per 
pound. 



Calch 

Ties. 
210 
180 
285 
205 
1,745 
295 
250 
350 
135 



185 
140 
220 
620 
380 
400 



As a rule the succulent roots, tubers, and bulbs contain larger 
quantities of water than the starchy vegetables and consequently 
have a lower nutritive value, pound for pound. The proportion of 
nitrogenous material which they contain is low, and of this small 
amount not more than a third, and frequently only a fifth, is in the 



4 BULLETi:^- 503^ U. S. DEPARTMENT OF AGRICULTURE. 

form of true protein. As regards carbohydrates, various sugars, 
pectose bodies, and, in some cases, pentosans, very generally con- 
stitute the reserve material which the plants store up instead of 
the starch, which is the principal carbohydrate in potatoes, sweet 
potatoes, etc. These facts are brought out clearly in figure 1, which 
shows the composition of common root vegetables in comparison 
with bread, and in figure 2, which makes a similar comparison 
between root vegetables, bread, and milk as sources of energy to the 
body. As a class these succulent roots are characterized by ver}^ 
marked flavors and odors, the flavor being due in part to the sugar 
and plant acids, and in part to the small amounts of volatile oils and 
similar substances which they contain and to which the odors are 
mainly due. Thus the peculiar flavors of turnips, radishes, onions, 
etc., are due chiefly to sulphur compounds. 

It is not enough to consider protein and energ}^ value in discussing 
food values. Mineral substances must be taken into account also, 
since they are essential for body growth and maintenance and for 
other physiological purposes. The need for iron in making red 
blood (hemoglobin) and the need for lime in making bone are well- 
known examples of the necessity for mineral substances. Work done 
in recent years has emphasized another important reason for sup- 
plying mineral matters in the diet, and from vegetable as well as 
animal food materials. It is now an accepted fact that the body 
performs its functions best when the tissues and fluids are either 
neutral or slightly alkaline and that different classes of food mate- 
rials, after they have been digested, leave the tissues and fluids of 
the body in different condition, some alkaline, some acid, and may, 
therefore, be spoken of as potentially acid or potentially alkaline. 
Many vegetables and fruits, owing to the presence of citric and 
other similar acids, are not alkaline when eaten but are potentially 
alkaline, because these acids leave behind an alkaline salt after 
being burned in the body. Foods rich in protein, such as meat, 
poultry, fish, and eggs, are potentially acid, because the sulphur and 
phosphorus which they contain are not completely burned but are 
partially left behind in the form of so-called fixed acids. It is 
to neutralize such acid residue that the potash and other salts of 
alkaline property supplied by fruits and roots and other vegetables 
are so valuable. Expressed in everyday terms, the results of labora- 
tory experiments show that when the diet contains such foods as 
meat, eggs, and fish, a generous supply of vegetable foods should 
be supplied also — an ample justification of the old household cus- 
tom of serving potatoes, turnips, beets, and other vegetables in 
abundance with meat. 



SUCCULENT ROOTS AND THEIR USE AS FOOD. 






cr^/p/por 





TIU/PA//?^ 









p/?or£-/A//.3^ 







^/?/5z^ /^o/pr/oA/ 



/^zK?r£yA/^.e9a 
B£'£T 





/Poor C£'L^/Pk^ 



>/?oz£yA/ AG-o^ cxi/?so/Ayz>/?/frjr/3.2. 



OA//OA/ 



^^7-0.3'^ 








Fig. 1. — Carrot, onion, beet, and other root vegetables compared in composition with 
each other and with bread. 



6 BULLETIX 503^ U. S. DEPAETMEXI OF AGEICULTUEE. 



S7;^A/£>^/?£> /no/p CO/^/^y^/P/SOM 







I I 



/Poor C£L£:/py tc//?a//^ oa//oa/ 

I I I 




I 



Fig. 2. — Energy value of edible portion of root vegetables per pound. Just as an 
engine must have fuel as a source of the power it supplies, so the body, which is 
a living engine, uses its food as fuel to supply the energy for the work it per- 
forms. For measuring the energy value of food the calorie is the most con- 
venient unit. It represents in round numbers the amount of heat required to 
raise 1 pound of water from 0" to 4° F., and equals very nearly 3,087 foot- 
pounds. If it be assumed that the large square at the head represents 1,000 
calories, the amount of energy which a pound of the different succulent vege- 
tables would supply is shown in graphic form by the black rectangles used for 
comparison. These values are, in general, low as compared with such a food as 
bread. Nevertheless, the succulent root vegetables as a group contribute ma- 
terially to the energy value of the diet in addition to furnishing material for 
the structural needs of the body. They are especially important for the mineral 
elements they supply, and in this respect rank high in comparison with other 
kinds of food. 



SUCCULENT ROOTS AND THEIR USE AS FOOD. 7 

In respect to final alkalinit}^, beets and carrots make the best 
showing of the succulent roots and are superior to all our common 
food materials except some of the green vegetables and fruits. Par- 
snips and radishes outrank potatoes; while turnips, which stand 
below potatoes, are yet higher than sweet potatoes.^ 

Though many vegetables are more economical sources of protein 
and energy than is sometimes realized, they are probably of even 
greater value for their ash constituents than for the carbohydrates 
and other organic substances which they contain. 

Furthermore, in considering the food value of vegetables, as of 
fruits, some of which are regarded merely as luxuries, one must not 
overlook the fact that they possess an actual advantage in enabling 
us to round out our dietary, as regards both bulk and palatability, 
without making the protein or energy intake excessive or compelling 
us to restrict the consumption of foods already in use. It can be said 
then, that a more liberal use of vegetables is to be encouraged ; and 
if the cost of the diet must be strictly limited, it is often wise to re- 
strict the use of some other food rather than this group. It should 
not.be forgotten, however, that the cheaper vegetables are fully as 
valuable for the purposes mentioned as are the expensive and out- 
of-season sorts. 

To sum up what has been said regarding the food value of the 
succulent roots, tubers, and bulbs, they are much less important 
food materials, when considered from the standpoint of the protein, 
fat, and carbohydrates which they supply, than are the concentrated 
cereal foods or even the starchy roots and tubers. They are, how- 
ever, very valuable in the diet for other reasons. The}^ furnish some 
nutritive material, and are appetizing and generally relished, and 
their use often makes palatable an otherwise flavorless dish or meal. 
Perhaps the most important function of these roots, etc., as indeed of 
most of our common vegetables and fruits, is to supply the body with 
mineral salts which are needed for the building and repair of tissue, 
for the proper carrying out of the physiological functions, and 
particularly, to insure the alkalinity of the tissues and fluids. 

Not many experiments have been made to test the digestibility of 
this group of vegetables. AYhat definite technical information there 
is indicates that they are much like other vegetables and fruits in 
this respect, being neither more nor less well assimilated than they 
are. Thus it has been found in the case of beets that 72 per cent of 
the protein, 97 per cent of the carbohydrates, and 90 per cent of the 
total energy were utilized by the bocl}^ 

lU. S. Dept. Agr., Office Expt. Stas. Buls. 185 (1907) ; 227 ( «10). Chemistry of 
Food and Nutrition. By H. C. Sherman. New York, 1911. Food -^-oducts. By H. C. 
Sherman. New York, 1914. 



8 BULLETIN 503^ U. S. DEPARTMEXT OF AGEICULTUEE, 

The ways in which these and other vegetables may be prepared 
for the table are very numerous and have been discussed in an earlier 
bulletin of the department.^ 

The various vegetables included in the table of composition have 
each some special characteristics which merit discussion, so the more 
important will be taken up separately. 

BEETS. 

Although the greater part of the total crop of beets is used for the 
j)roduction of sugar or for the feeding of farm animals, beets are 
used in such large quantities as a human food that they rank as one 
of the most common table vegetables. AYliite or yellow table beets 
are occasionally seen, but the red ones are the most usual. The flavor 
is more delicate in the summer varieties than in the later maturing- 
sorts. Each year the southern-grown beets are becoming more com- 
mon in our winter market and are superseding the large, fully 
matured roots which were formerh^ so often stored as winter vege- 
tables and which, late in the season, often develop a rather bitter and 
unpleasant flavor. It is sometimes said that beets are more nutritious 
than turnips, carrots, etc., but a comparison of the values for average 
composition given in the table (p. 3) does not substantiate this 
statement, all these vegetables being very much alike as regards the 
proportion of nutritive material present. 

Cane sugar constitutes a considerable portion of the total carbo- 
hydrates of beets, as high as 10 per cent or more having been often 
reported. Some reducing sugar is also present. In the varieties of 
beets grown for sugar making the percentage of cane sugar is con- 
siderably higher, sometimes 20 per cent or more, though such high 
values are the exception. Beets are sometimes said to be very rich 
in cellulose, but this does not seem to be the case with American 
varieties whose average composition has been quoted. When beets 
are cooked, a part of the sugar and other soluble nutrients wliich 
they contain is extracted, but how much material is removed can 
not be stated, as no cooking experiments with beets have been found 
on record. 

Beets are frequenth' canned at home for winter use, and the com- 
mercial canned article is a very well known product. The canned 
goods have practically the same chemical composition as freshly 
cooked beets. Some of the girls' canning clubs, which the State and 
county organizations and the United States Department of Agri- 
culture are conducting in cooperation, have put up young beets with 
the tops left on, or have canned both beets and tops together — an 
excellent way of providing iron-rich greens in the winter diet, as 
h2Q^ tops make a Aer}^ palatable potherb. 

lU. S. Dept. Agr., Farmers' Bui. •2~^(^ nOOG). 



SUCCULENT ROOTS AND THEIR USE AS EOOD. 9 

CELERIAC. 

This vegetable, which is also known as turnip-rooted celery, or 
knob-celery, is closely related to ordinary celery, being indeed a cul- 
tured variety of the same plant grown under conditions which have 
developed the root rather than the stalk. In Europe it is by far the 
most common form, but it has never been extensively cultivated in 
the United States, though it is found in the larger markets. The 
roots are white and more or less globular in shape, closely resembling 
turnips in appearance. As the figures in the table on page 3 show, 
they have much the same general composition as the other succulent 
roots and tubers. Mannit, a starch-like carbohydrate, and also small 
amounts of asparagin, a characteristic constituent of asparagus, have 
been reported present in tuberous- rooted celery. This vegetable has 
a pronounced celery flavor, due apparently to a complex oil like that 
in the seed, which is rather stronger or more abundant in the raw 
root than in the tender celery stalks. When cooked, celeriac does 
not differ very greatly in taste from the ordinary stewed celery. 
The leaves and stalks of celeriac are used for seasoning, and particu- 
larly as soup greens. 

It is often said that celery is a nerve food, but there seems to be no 
warrant for such a statement, and the belief is probably a survival 
of the time when specific virtues were attributed to almost all plants 
and vegetables. 

CARROTS. 

Carrots are grown in many varieties and vary greatly in color, size, 
flavor, and other characteristics, those most commonly raised for the 
table being of medium size, deep-yellow color, tender, and of deli- 
cate flavor. Young carrots are much more satisfactory than old ones, 
as the latter tend to become hard and woody, especially at the core, 
while not infrequently the flavor of old carrots is disagreeably strong. 
Some varieties are more satisfactory than others for winter use, but 
winter carrots are, generally speaking, more used for seasoning soups 
and other dishes than as a table vegetable. Improved methods of 
transportation, storage, etc., have moreover, made the small, tender, 
southern-grown carrot comparatively common as a winter vegetable. 
It is not difficult to can carrots for home use, as has been proved by 
the girls' canning clubs. 

In composition carrots do not differ very materially from other 
similar roots, carbohydrates constituting the principal nutritive ma- 
terial. Sugar is an important constituent, 12 per cent or more being 
sometimes present, though perhaps 5 or 6 per cent would more nearly 
represent the average. Small amounts of pentosans have also been 
reported. Carrots owe their color to the presence of a yellow organic 
70537°— Bull. 503—17 2 




10 BULLETIX .503^ r. S. DEPAETMEXT OF AGEICE^LTL'EE. 

compound knoTrn as carotin, which has been extracted Trith the juice 
and used for coloring butter. 

The water in which carrots have been boiled is yellow in color and 
has a sweet taste, plainly showing that some of the nutrients have 
been removed in the process of cooking. Experiments have shown 
that whether the water is hot or cold at the start makes less difference 
than in the case of potatoes, but the more water used, the greater 
are the amounts of food materials extracted. On the other hand, 
the more rapidly the carrots are boiled, the smaller is the amount 
extracted. This means that quick cooking in a 
small quantity of water is an economical pro- 
cedure. Figure 3 represents in graphic form 
\yMrs/p ^Y\Q composition of the carrot and the loss of 
nutrients when boiled. Much less material is 
lost when the carrots are -cooked by steaming. 
The materials extracted from the carrots in 
cooking consist principally of sugar or similar 
'a^^o//>-zypy4r^ carbohydrates. If the water in which they or 
other such vegetables are cooked is saved and 
^ „ ^ . . , used in soup makino- or in a similar wav, anv 

Fig. 3. — Composition and ^ ^ . .. 

loss (shaded portion) real loss Can be avoided. 

of food material in Carrots are cooked in manv wavs and quite 

boiling carrots. " *- -^ 

generally liked. They are also much used as a 
seasoning vegetable. Less commonly than was once the case, they 
are used with orange, lemon, or other flavoring in domestic jam 
making, carrot marmalade being an old favorite. 

Dried or dessiccated carrots are on the market and are used to some 
extent where small bulk and good keeping qualities are important 
considerations. These goods resemble the fresh carrots in composi- 
tion, except that they have been concentrated by the evaporation of 
water. 

PARSNIPS. 

Parsnips belong to the same botanical order as carrots and re- 
semble them in form and general habit of growth. The flesh of 
the root, however, is paler, being white or light-cream color, and 
the flavor is quite distinct and very pronounced. Parsnips may be 
kept in the ground over winter and are especially welcome additions 
to the diet in early spring, when vegetables which have been stored 
are losing their good qualities. For some reason boiled parsnips 
were long considered in some regions of Europe to be the proper 
vegetable to serve with salt fish, but this tradition is not followed in 
the United States, plain boiled or fried parsnips being commonly 
served with roast meats of any sort. They are also used for soups, 
for fritters, and so on. 



SUCCULENT ROOTS AND THEIE USE AS FOOD. H 

As regards composition, parsnips are much like the other roots 
and tubers, but contain rather higher quantities of cellulose, par- 
ticularly in the core, which becomes stringy and woody when the 
roots are bid. How much of the total nutritive material is lost in 
boiling is not definitely known, but it is commonly thought to be 
considerable. The amount is doubtless affected by the same condi- 
tions as were noted with carrots. 

SALSIFY. 

The name "salsif}^" is applied to three distinct vegetables; the 
common white salsify {Tragopogon porHfolius)^ known also on 
account of its flavor as oyster plant or vegetable oyster, black salsify 
{Scorzonera Mspanica) , the Schwarzwurzel of the German, and the 
so-called Spanish salsif}^ {Scolymus hispanicus) . The first of these 
is very commonly grown in the United States, and black salsify is 
also grown to a limited extent, while Spanish salsify is seldom cul- 
tivated. Both common salsify and black salsify closely resemble the 
other succulent roots used as food in general character. One dis- 
tinction, however, is t^iat the principal carbohydrate stored in black 
salsify is inulin rather than starch, and so this vegetable has some 
reputation for use in the diet of diabetics. Since the salsifies are not 
injured by mild frosts, they may be left in the ground until late 
winter or early spring. 

RADISHES. 

The radishes most commonly grown in the United States are the 
small ones with red exterior and white flesh, although white and 
dark-purple varieties and larger kinds are also well known. Though 
formerly red radishes were a typical spring or early-summer vege- 
table, they are now so commonh^ grown under glass that they are 
available all winter in large markets. To be at their best, rad- 
ishes should be eaten before the roots are fully mature and should 
be very fresh. Besides losing their crispness^ they become sweeter 
in taste if they are kept long after they are gathered, owing to the 
action of a ferment or enzym normally present which changes part 
of the radish starch to sugar. Similar enzyms are found in beets, 
carrots, etc., but in these vegetables the action is less marked. 

As will be seen from the figures in the table (p. 3) , young radishes 
contain even more water than turnips. (See also fig. 1, p. 5.) The 
characteristic pungent flavor is due to organic compounds containing 
sulphur, similar to the essential oil in mustard. Kadishes are so 
succulent and tender that they are doubtless well assimilated, though, 
as far as can be learned, their digestibility has not been studied. It 
is frequently said that the}^ are productive of digestive disturbances, 
but such disturbances are by no means general, and when they occur 



12 BULLETIX 503, U. S. DEPAETMEXT OF AGEICULTUEE. 

may be due to insufficient mastication — a common occurrence in the 
case of succulent foods. 

Besides the conunon radish, of which the pink or red form is the 
best known, tliere are larger sorts, sometimes called turnip radish, 
which are wliite or purplish in color. These are at their best in 
summer, but have such good keeping qualities that they may be held 
over for winter use. Though common in many American markets, 
these larger varieties are less well known than in parts of Europe. 
There is also a large variety of Japanese radish which has been 
gi'own to some extent in the United States. 

Though most commonly eaten raw, radishes, esj^ecially the larger 
sorts, are also cooked and served like creamed turnip, which they 
much resemble in flavor. The leaves can be used for greens, or if 
they are very tender can be added to salads. The young and tender 
seed pods of some varieties are sometimes used for pickling like 
capers; in fact, the Madras or rat-tail radish is grown exclusively 
for its pods, which are cooked and also used in pickle making. 

TURNIPS. 

Many varieties of turnips are grown throughout temperate cli- 
mates, some of which are coarse in texture and used as food for farm 
animals, while others are raised as table vegetables. There is con- 
siderable variation in the color, flavor, and composition of the turnip, 
there being two groups commonly distinguished, one having leaves 
with a smooth surface and glaucous bloom and called '* Swedes " or 
"rutabagas.*' Turnips are usually white-fleshed and rutabagas yel- 
low-fleshed, though the distinction does not always hold good. In 
the summer the early white varieties are usually preferred in spite of 
the fact that the}^ are more watery, while in winter the yellow turnips 
are more commonly used. Solid as the turnip roots appear, they 
contain on an average about 89 per cent of water, or a trifle more 
than is found in whole milk. The total amount of nitrogenous sub- 
stance is small, and only about 20 per cent of the total present is in 
the form of true protein. Carbohydrates are the principal nutritive 
material, glucose, cane sugar, pectose, pentosans, and crude fiber 
being the characteristic forms. The flavor of the turnip, like that of 
its relatives, the cabbage and the radish, is due principally to com- 
pounds of sulphur, which are so volatile that when turnips are fed 
to cows these compounds pass through the body tissues and into the 
milk and give it an unmistakable flavor. In cooking, these pungent 
substances are broken down to some extent and pass off into the air. 

KOHL-RABI. 

Kohl-rabi, or turnip-rooted cabbage, represents a curious variety 
of the turnip and cabbage family in which the reserve material of 
the plant is stored in an above-ground tuberlike enlargement of the 



SUCCULENT ROOTS AND THEIE USE AS FOOD. 13 

stem just above the seed leaves or cotyledons. Although, strictly 
speaking, it does not belong to the roots and tubers, it is so similar 
to them in composition, in methods of cooker}^, and in uses that it has 
been included in this discussion. Kohl-rabi is considered best in the 
early summer, when it is still young and tender, but it is commonly 
found on the market until late fall. In flavor it is more delicate 
than either the turnip or cabbage, though it resembles them more 
nearly in this respect than it does other common vegetables. Like 
turnip, it can be diced, cooked, and served with butter or cream 
sauce. It can be cooked with other vegetables with salt meat in a 
" boiled dinner," or sliced and used in soup as a seasoning vegetable. 
Kohl-rabi leaves if not too tough are excellent when cooked as greens, 
and may be served as a border around the kohl-rabi or as a separate 
dish. 

ONIONS, GARLIC, AND SIMILAR VEGETABLES. 

These plants are prized for use alone and for the flavor they im- 
part to other foods, so they can be classed both with succulent roots 
and with those used as condiments. Onions are so frequently eaten 
as a vegetable that it seems logical to discuss them primarily in com- 
parison with such materials as beets, radishes, etc. 

All the members of the onion family are characterized by very 
strong flavor and odor, due to the presence of allyl sulphid, an oil- 
like organic compound of sulphur. Different varieties vary some- 
what in flavor and composition, and the flavor is usually more pro- 
nounced in the bulbs and roots than in the leaves or other parts, and 
in old than in young plants. The flavor-yielding material is very 
volatile and is broken down by heat to some extent. Consequently, 
the cooked vegetable has a milder flavor than the raw. 

In the United States the common onion in its many varieties is 
the best known and most used member of the onion family. The 
bulbs vary in size from the tiny pearl onions used for pickle making 
to the very large Spanish onions weighing a pound or more each. 
The range in color is also wide and varies from silver white, cream 
white, green, or yellow to red or reddish purple. The total crop pro- 
duced is very large, and quantities are also imported from southern 
Europe, Bermuda, and the West Indies. As with most vegetables, 
the young and somewhat immature onions are preferred to the fully 
matured bulbs, though the latter have the best keeping qualities. In 
general, white varieties are milder in flavor than the red or yellow 
sorts and are generally preferred as table vegetables. If they are to 
be kept through the winter, onions should be taken from the ground 
as soon as the stalks begin to wither and cured or dried in the air 
for about 10 days. If moist when stored they will not keep well. 

The proportion of water and nutrients in onions varies greatly, 
not only with the variety but with the stage of growth and the 



14 BULLETIN 503^ U. S. DEPARTMENT OF AGEICULTXJEE. 

method of storing them. Roughly speaking, the chemical composi- 
tion is very similar to that of the succulent roots included in the table 
(p. 3). Onions contain, however, rather larger quantities of cellu- 
lose, particularly in the outer layers, which is a reason wlw these are 
usually removed before cooking. The waste in peeling and trimming 
onions (fig. 4) for the table may be as high as 50 per cent, but 20 
or 30 per cent is perhaps a fair average. They are commonly con- 
ceded to be wholesome and have been prized since the earliest times 
as a valuable addition to the diet. The characteristic sulphur com- 
pound which the}^ contain is believed to stimulate the flow of diges- 
tive juices, and this and other constitutents have a desirable effect 
in overcoming a tendenc}^ to constipation. As onions contain no 
appreciable amount of starch and little sugar, they are commonly 

allowed to invalids from 
whose diet starchy foods 

Garlic is a member of 




are excluded. 



fv/7-// <r^>as^z ^£-^^A^s^ /.OSS the onion tribe which pro- 

duces a collection oi small 
bulbs called " cloves " in 
the place of one large bulb. 

Fig. 4. — Loss in peeling and trimming onions. r>i /> i -i i • • 

feome 01 the mild varieties 
grown in the Mediterranean region are eaten as vegetables, but in 
this country garlic is used mainly as a flavoring. Even so, its use is 
uncommon except among persons of foreign birth or food habits, and 
this seems unfortunate, as, rightly used, garlic may acid to the pala- 
tability of salads, meats, and other dishes. 

Shallot, cibol, etc., ai^ varieties of the onion family yielding bulbs 
which are much esteemed for their flavor in Europe, though they are 
not common in the United States. Leeks and chives, two other sorts, 
develop almost no bulbs and are grown for their leaves, leeks being 
used as a green vegetable or potherb and chives mainly for seasoning. 
Although most families in the United States are familiar with onions, 
they do not generally know the similar vegetables. However, pro- 
fessional cooks consider that the other members of the group are well 
worth using and that some of them are almost indispensable for 
seasoning purposes. 

As is the case with so many of the succulent root vegetables, the 
green tops of onions and leeks are excellent cooked as greens. 

ROOT VEGETABLES LESS COMMONLY KNOWN. 

In other parts of the world, or in other times, many succulent roots 
have been used as food which, though known in the United States 
and grown to some extent, are seldom seen on our tables. Some of 
them might well be more commonly known, while others are suffi- 



SUCCULEI^T ROOTS AND THEIR USE AS FOOD. 15 

ciently interesting for one reason or another to be worth at least 
brief mention here. 

Chervil is a plant, two forms of which are common in Europe. 
One of them {Anthnscus cerefolium) is sometimes called sweet cicely 
and is cultivated mainly for its leaves, which are used as a salad. 
The other, known as tuberous or turnip-rooted chervil {Chcerophyl- 
luTYh hulhosuvi) ^ is a true root vegetable. The roots are about the 
size and shape of small carrots and are gray or blackish on the out- 
side, with yellow-white flesh and with a distinctive flavor. They are 
used in much the same way as young carrots. Seedsmen offer the 
seeds, but they have never been common in the United States. 

The chufa, or nut grass, or earth almond, for it is known by all of 
these names, is the small tuberous root of a sedgelike plant which 
has a flavor suggesting nuts. A native of southern Europe, it is now 
cultivated in many countries. Though used as a food in a limited 
way, it is chiefly important as a feeding stuff. The chufa nuts are 
well known to children in the Southern States. 

The bulbs of various lilies are eaten in the Orient and are on sale 
in Chinese quarters and served in Chinese restaurants in many Ameri- 
can cities. The American Indians ate and to a small extent still use 
lily bulbs or corms, both roasted and raw, including the Indian 
cucumber {Medeola virginica) ^ a relative of the trillium, the roots of 
water lilies, and many other wild roots, few of which have been taken 
over into the diet of other peoples. 

ROOTS USED AS CONDIMENTS. 

Several roots have pronounced aromatic qualities which give them 
a conclimental value quite independent of the nutritive material 
which they contain. In addition to increasing the flavor of foods, it 
seems possible that such condiments may stimulate the flow of diges- 
tive juices as well as please the palate. Horse-radish and ginger are 
the most common condimental roots, though chicory, so commonly 
considered in Europe a palatable addition to coffee, may also be men- 
tioned, as well as licorice root and calamus, or sweet flag, and wild 
ginger, or snakeroot. 

Horse-radish is a moisture-loving plant of the mustard family 
which is cultivated throughout north-temperate countries and is 
very frequently found wild in the United States, as it long ago 
escaped from cultivation. The root is long, rather slender, and has 
a sharp, peppery flavor, owing to the presence of an essential oil 
which much resembles in general character that in the radish and 
other members of the mustard family. As regards composition, 
horse-radish contains on an average 86.4 per cent water. 1.4 per cent 
protein, 0.2 per cent fat. 10.5 per cent total carbohydrates, and 1.5 



16 BULLETIN 503^ U. S. DEPAETMENT OF AGKICULTURE. 

per cent ash, and has a fuel value of 225 calories per pound. Its 
water content is so high that it may be grouped with the succulent 
roots in spite of the fact that starch constitutes the principal carbo- 
hydrate present. As might be expected from the stringy character 
of the roots, the percentage of crude fiber is rather high. Though 
certain A^arieties of horse-radish are sometimes cooked as a vegetable 
and it is used for seasoning pickles, for making sauces,^ to serve with 
meat, etc., its most common use in this country is as a condiment, 
when it is mixed with vinegar. It is popularly supposed that the 
vinegar softens the crude fiber to some extent and makes it more di- 
gestible. 

Ginger, the underground rootstock of the ginger plant {Zingiber 
officinale)^ is perhaps most frequentl}^ used dvy as a spice, though 
the fresh root or green ginger is common in autumn, being used in 
pickle making, preserving, and in other ways. Large quantities of 
ginger root are preserved in rich sugar sirup, " Canton ginger " in 
its round stone jars being an old-fashioned confection which is still 
much prized. The crystallized or candied ginger is even more com- 
mon ; it, like preserved ginger, is frequently served as a sweetmeat. 
It is also used in making desserts of various sorts ^ and is generally 
used like candied fruits, ^¥hile the nutritive value of preserved 
or crystallized ginger depends, of course, quite largely on the 
added sugar, the fresh root contains some nutritive material, the 
average composition being 85.6 per cent water, 1 per cent pro- 
tein, 0.6 per cent fat, 11.4 per cent sugar, starch, etc., 1 peir' cent) 
crude fiber, and 1.4 per cent ash, and has a fuel value of 240 calories 
per pound. Of the total fat or ether extract, about half consists of 
the ethereal oil which, together with a pungent, nonvolatile con- 
stituent called gingerol, gives to ginger its characteristic flavor. The 
young and tender ends of the branching root, or rhizome, called 
ginger buds, are the most delicate portion as regards both texture 
and flavor. 

Calamus, or flagroot, is found wild in Europe, as well as in the 
ITnited States, and has long been known for its pungent and aromatic 
flavor. The root is most often gathered, though the young blossom 
portion is also eaten and has a specially mild flavor. Flagroot was 
used for a seasoning in earlier times in England and in the United 
States also, where it is still used to a limited extent like candied 
citron to flavor stewed fruit and so on, though its use at the present 
time is very largeh^' limited to the candied flagroot which house- 
keepers often make at home and which is also a commercial product. 

^U. S. Dept. Agr., Farmers' Bui. 391 (1910), p. 27. [Recipe for making horse-radish 
sauce.] 

2U. S. Dept. Agr., Yearbook 1912. pp. 505-552. Raisins, Figs, and Other Dried Fruits 
and Their Use. 



SUCCULENT ROOTS AND THEIR USE AS FOOD. 17 

Wild ginger {Asarum canadense) ^ or the snakeroot of our northern 
woods, may also be mentioned. The spicy, aromatic root of this 
plant was gathered quite commonly in earlier times and dried, being 
used like many other wild plants in domestic medicine. Its use as a 
condiment was also common, a bit of the dried root being carried 
about and nibbled at odd times in the same way as calamus and dried 
orris root. In pioneer cookery it occasionally took the place of some 
more common spice, and does now, the fresh root being used to some 
extent like true ginger in pickle making. It also can be candied. 

Laboratory tests have shown that both flagroot and wild ginger 
root used in cookery in small quantities in place of other spices give 
a distinctive flavor which many would consider pleasant. 

Another native American root — sassafras — which has some impor- 
tance for condimental purposes, may be mentioned here. The bark 
of the root yields a flavoring extract more used in confectionery 
making than in the home. However, it is interesting to know that 
tea made from this root, which was once so common a beverage 
under the name of " saloop," is still used to some extent in parts of 
the United States, both in the home and commercially. 

SUMMARY. 

The plants which store their reserve material in underground 
roots, tubers, and bulbs have, in many instances, come to be regarded 
by man as among the most important foodstuffs. Cultivation has 
to a great extent modified the size, structure, flavor, and appear- 
ance of the parts which are eaten, and the garden varieties are as 
a rule superior to the wild in these respects and show important 
modifications in the season of growth and in other ways. As a 
class the edible roots, tubers, and bulbs may be divided into the 
following groups: (1) Starch-yielding vegetables, as potatoes, sweet 
potatoes, dasheens, etc.; (2) succulent roots, as beets, carrots, and 
parsnips; and (3) condimental or flavoring roots, as horse-radish 
and ginger. 

The edible roots, tubers, and bulbs have a high water content 
and are valued as additions to the diet for their appetizing, succu- 
lent qualities and the bulk which they give, as well as for the nutri- 
tive material which they supply. Starch is the material most com- 
monly stored in the underground receptacles, though it is replaced 
in some plants by closely related bodies such as inulin, mannin. etc., 
by sugars of different sorts, pectoses. or other carbohydrates. The 
proportion of nitrogenous material in such foodstuffs is small, and 
true albumin seldom constitutes more than a third of the total pro- 
tein. The proportion of fat is also small, being composed in some 
cases very largely of wax-like bodies found in the skin, or of color- 
ing matter; and in other cases, of volatile oils and similar sub- 



18 BULLETIN 503, U. S. DEPARTMENT OF AGEICULTUEE. 

stances, which give the plants their characteristic flavor and odor. 
Mineral matter is an important constituent of these vegetable foods, 
the proportion, though small, being about the same as is found in 
many other common articles of diet. Sodium, potassium, iron, sul- 
phur, and phosphorus compounds are the common mineral con- 
stituents. As the mineral matters exist in combination with organic 
acids and other bodies, they contribute materially to the flavor of the 
tubers, roots, etc. 

Beets, carrots, parsnips, salsify, turnips, and onions are the mo^ 
common of the so-called succulent root crops used as food. They 
differ from starch-yielding vegetables like potatoes mainly in con- 
taining a larger proportion of water, 85 to 90 per cent on an average, 
and consequently a smaller proportion of nutritive material. Further- 
more, it is generally true that starch is not the characteristic carbo- 
hydrate of these vegetables, its place being taken by sugars of differ- 
ent sorts, pectose bodies, and other similar carbohydrates, while the 
percentage of crude fiber is also rather higher than in the edible 
starch-yielding roots and tubers. Many of the vegetables included 
in this group are characterized by marked flavors and odors due to 
the presence of volatile organic sulphur compounds in their juices. 
In the members of the onion tribe these are especially strong, and 
some varieties are used almost exclusively as flavoring materials, 
while other and milder sorts are also used in large quantities as table 
vegetables. 

' Though not very nutritious in proportion to their bulk, root crops 
as a class offer some advantages over most other vegetable foods. 
They are so easily grown and so productive that under ordinary con- 
ditions the}^ sell at prices within the reach of all. Many of them 
may be kept over w-inter in such good condition that they are prac- 
tically never out of season, or are in season when other vegetables are 
scarce. The carbohydrates, the principal nutritive material present, 
are in forms which are readily and well assimilated. The character- 
istic flavor which some of these vegetables possess is a decided ad- 
vantage, as it makes the vegetables palatable and adds to the variety 
of the diet. Succulent vegetables of all sorts contribute bulk to the 
diet and so are valuable from the standpoint of hygiene, because 
within limits bulkiness is a favorable condition for normal digestion 
and also of importance in overcoming a tendency to constipation. 
They are among the important sources of necessary mineral matters 
in the ordinary diet. Since the body performs its functions best if 
its tissues and fluids are either neutral or slightly alkaline, and since 
vegetables tend to produce that effect, they have a special value as 
regulators of the body processes. 



PUBLICATIONS OF THE DEPARTMENT OF AGRICULTURE OF 
INTEREST IN CONNECTION WITH THIS BULLETIN. 

AVAILABLE FOR FREE DISTRIBUTION BY THE DEPARTMENT OF AGRICULTURE. 

Potatoes, Sweet Potatoes, and Other Starchy Roots as Food. (Department 

Bulletin 468.) 

Principles of Xntririon and Nurriiive Value of Food. (Farmers' Bulletin 

142.) 

Preparation of Vegetables for the Table. (Farmers' Bulletin 256.) 
Potatoes and Other Root Crops as Food. (Farmers' Bulletin 295.) 
Care of Food in the Home. (Farmers' Bulletin 375.) 
Storing and Marketing Sweet Potatoes. (Farmers' Bulletin 548.) 

FOR SALE BY, THE SUPERINTENDENT OF DOCUMENTS, GOVERNMENT PRINTING 
OFFICE, WASHINGTON, D. C. 

Extension Course in Vegetable Foods. (Department Bulletin 123.) Price, 
10 cents. 

Cassava. (Farmers' Bulletin 167.) Price, 5 cents. 

Losses in Boiling Vegetables and Composition and Digestibility of Potatoes 
and Eggs. ( Office of Experiment Stations Bulletin 43. ) Price, 5 cents. 

Course in Use and Preparation of Vegetable Foods for Movable and Corre- 
spondence Schools of Agriculture. (Office of Experiment Stations Bulletin 
245.) Price, 10 cents. 

19 



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